1. Field of the Disclosure
This disclosure generally relates to an interactive input device and, more particularly, to a capacitive touch device, a capacitive communication device and a communication system.
2. Description of the Related Art
Capacitive sensors generally include a pair of electrodes configured to sense a finger. When a finger is present, the amount of charge transferring between the pair of electrodes can be changed so that it is able to detect whether the finger is present or not according to a voltage variation. It is able to form a sensing matrix by arranging a plurality of electrode pairs in matrix.
FIGS. 1A and 1B are schematic diagrams of a conventional capacitive sensor which includes a first electrode 91, a second electrode 92, a drive circuit 93 and a detection circuit 94. The drive circuit 93 is configured to input a drive signal to the first electrode 91. Electric field can be formed between the first electrode 91 and the second electrode 92 so as to transfer charges to the second electrode 92. The detection circuit 94 is configured to detect the amount of charges transferred to the second electrode 92.
When a finger is present, e.g. shown by an equivalent circuit 8, the finger may disturb the electric field between the first electrode 91 and the second electrode 92 so that the amount of transferred charges is reduced. The detection circuit 94 can detect a voltage variation to accordingly identify the presence of the finger.
In addition, when another capacitive sensor approaches, the electric field between the first electrode 91 and the second electrode 92 is also changed thereby changing the amount of transferred charges. The detection circuit 94 is also able to detect a voltage variation to accordingly identify the presence of said another capacitive sensor.